While lift and duration are most often discussed when talk turns to cam timing, there is a third variable that has a decided effect on both power and personality. Has anybody experienced it/ tried it? As a result, you can enjoy a pleasing engine outcome. If you look at the cam card, you will find a maximum lift column on the card.Now, all you have to do is, add up the two mentioned maximum angles and divide the summation by 2. by bug1914 Tue May 13, 2003 2:56 am, Post Some prefer a narrow powerband, and some prefer the broader one. If that accessory still does not assist the cam in producing enough vacuum, then as a last resort you can use a vacuum pump. The extra cubic inches will smooth out a rough idle in a 327. Things like idle vacuum, fuel economy, and tuning all factor into picking the right cam. A narrow, more specific power band is also a product of a narrow LSA, as is a lumpy idle qualityoften referred to as the 106 sound. 108 versus 110 will drive the power band down. Retarding the camshaft (a higher intake lobe centerline number 108 vs. 104) will generally start the power band later in the RPM range and decrease the cylinder pressure. I had an XE 274 in it. Frankly cams with a 108-114 lca unless in the perfect combo you won't usually see more than 15hp and you won't really feel the difference except for either a peaky or broad power band. The center of those 2 events is the LOBE CENTERLINE (ECL). This cam also offered the highest torque output at 4,000 rpm with 522 lb-ft. Based on the peak numbers alone you might be tempted to grab the one with the tightest (108-degree) LSA, but there is more to a cam test than power. It is dangerous to be right in matters on which the established authorities are wrong. The other thing is that you need to tune your ignition advance to maximize your performance. JavaScript is disabled. So, which is better? by farmer Mon May 12, 2003 3:14 pm, Post To further minimize any dyno variations, the engine's oil and water temperatures were kept the same for each pull. by mike thompson Tue May 13, 2003 4:03 am, Post Defining Lobe Center and It's Importance to Engine Performance: A Blog. A 232 deg duration cam with a 108 deg LCA will have the same valve overlap as a 236 deg cam with a 110 deg LCA and idle will probably be very similar. Tight LSA cams make excellent low-end torque and have a beautiful power curve. by trmnatr Sat Dec 06, 2008 10:45 pm, Post document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); Disclaimer: Remember to always consult with an expert first before trying anything at home. somthing to that aspect. This may be of concern if you have vacuum assisted accessories, such as power brakes or steering. It provides a spark plug with the high voltage needed for combustion. I have 108 for LSA and my headlights take awhile to go up when the car is idling. Lobe seperation cant be seperated from duration,the 2 are connected.the old duntov cam had a lot less duration than many new cams so the valve overlap was not extreme and the engine ran with a gentle lope.Increase the duration by 20* and this cam would shake a 283 out of the car at idle,but then increase the lobe seperation by 4* and the motor will have a gentle lope again. Camshaft: Hydraulic Roller, Comp Cam custom grind (ADV Duration 281-287,@ .050 230-236, lift 622I & 625E w/1.6 rockers.) Wide LSA cams are also applicable in forced-induction applications where less exhaust overlap is required. It made 472.4 lb-ft at peak, a 21.5lb-ft disparity from the 101 cam. I'd run it, just be sure to check valve to piston clearance, coil bind and retainer to guide boss/seal clearance. Come join the discussion about restoration, builds, performance, modifications, classifieds, troubleshooting, maintenance, and more! JavaScript is disabled. Like one cam is 112 degree and the next is 108 the 108 cam will allow less "leakage"? I also like the 106 lobe separation with the intake on 103. Like choosing a cam in general, the key to eliminating separation anxiety is to find the proper balance of driveability and performance. Due to the tightness and frequent overlapping of the intake and exhaust valves, the engine cant generate the high RPM as it is supposed to. The second cam would have a rougher idle, produce more torque and would rev quicker. Another important measurement was the torque production at 4,000 rpm and this cam checked in with 484 lb-ft of torque. It's wet flow tested at 690cfm. 106 LSA: There is a scale of standard cranking compression of the engine. It is the average centerline between both lobes and expressed in degrees ranging from 95 on the extremely narrow/tight side to upward of 120 on the wide end. Whatever you do, stay under 270 advertised duration and shoot for a 110 lobe separation. The 114 cam will give more low end torque, good midrange, less power up high. Not a HUGE, but a significant difference between 110 and 112, but those are the trends. The 110 is probably a better choice for a performance street engine. Lobe Separation Angle "LSA "Jump to Latest Follow 1 - 17 of 17 Posts . Torsion Beam Vs Multi Link: Who Wins the Battle? I know a little about cams. For a better experience, please enable JavaScript in your browser before proceeding. A good amount of idle vacuum or increased idle vacuum found at 110 LSA advances the engines efficiency. That notion is completely false. Tests have shown that, for a given cam profile, a tighter (smaller) lobe center will produce more average horsepower and a quicker revving engine. A wide lobe seperation is not always better than a narrow one, or vise versa. . Anybody do any real testing on LSA in a 3.75 stroke small block chevy?I have always used 104-106 and was thinking about trying a 108 or 110 design.I know there is a lot of variables but just a general opinion from any experts.This is for motor only no nitrous.600-640 HP engine combos.Much appreciated! It's the scavenging effect of the high velocity exhaust gases rushing out that pulls the fresh fuel/air charge into the chamber. The Fora platform includes forum software by XenForo. Anybody here run a 108 LSA? I've seen that Webcam cams can be ordered with either of the above. On the cranking. I normally run a 106 to a 108 because I like the "hit" a tighter LC cam has when it come up on the came. Professionally ported & polished iron 4V head with titanium intake valves, stainless exhaust, titanium retainers & keepers & dual springs. Re: Lobe separations on 383-406 cids.104-106-108-110. The wider lobe separation angle closes the intake valve later and reduces cylinder pressure, so that is where it's detonation resistance comes from. 108 vs 112 lobe seperation. "Ninety-nine percent of cranking compression is dictated by static compression ratio and intake-valve closing point," said Comp Cams' Billy Godbold. According to the Motortrend, LSA (Lobe Separation Angle) is a wonderful approximation of the operation of the engine because it takes into account the relative time of the intake-valve events (intake opening, intake closing) and the exhaust-valve events (exhaust opening, exhaust closing) concerning each other.Above mentioned sequential activities allow LSA to be an accurate representation of the operation of the engine. You must log in or register to reply here. The piston and cylinder damage possibility is pretty low at 110 LSA. 238/248 duration, 300/310 adv. I'd also go to a 110-112 lobe separation angle. Aug 20, 2006. by ANT Mon May 12, 2003 1:47 pm, Post In terms of horsepower, the disparity between all three cams was only 6.5 hp, with a scant 100 rpm separating the peaks. 1-4 It is one of the most common neurological disorders worldwide, 1-5 is among the most common . It is the angle that separates the intake and exhaust lobe for a particular cylinder, and is measured in camshaft degrees. If it occurs too late, it will lean out the cylinder and greatly hinder the performance of the engine. My duration will be about 230 degrees. Epilepsy is a chronic noncommunicable brain (neurological) disorder associated with excessive neuronal activity and unprovoked seizures referred to as 'epileptic seizures' and sensory-motor deficits that cause neurobiological, cognitive, psychological, and social consequences to the patient. Realize what the engine is going in, however, as you may not be able to use the wildest cam out there. So, now you, Read More Chevy Transmission Wont Shift Into 3rd: Finding the Main CulpritContinue, While changing the oil on your boats lower unit, you may need to change the drain plug, too. by SStrokerAce Sat Dec 06, 2008 7:38 pm, Post The 110 is probably a better choice for a performance street engine. But remember, although a broader powerband has a couple of acceleration advantages, it also comes with a few drawbacks. i've heard of this being done something about the massive amounts of duration allowes gasses to disipate? A cam card with its myriad numbers, acronyms, and abbreviations is one red-pen stroke away from a failed math test. *If you do not have enough vacuum, you can in some cases install a vacuum canister or reservoir, which works by storing the peak vacuum in the reservoir. For a better experience, please enable JavaScript in your browser before proceeding. Either learn to fix it, or learn to write checks. And better gas mileage. As usual, Marc (aka Master) is correct. dont sound like a verry street friendly motor butany thoughts? 1-3 Cognitive impairment is common in both FLE and TLE and adversely impacts quality of life and psychosocial functioning. The world of fuel injection is where wide LSA cams like the 113 really shine. Ed JTO learn to park Joined May 31, 2009 180 Posts I think that cam had 110 lobe sep. Im loking at a summit cam with close to the same lift and duration #s but 114 lobe sep. The standard bore block was then stuffed with a 4340 forged steel 4.0-inch crank and 6.125-inch rods, along with a set of flat-top, forged JE pistons. not exactly true, Ive seen custom grinds that are on 108 lca, smooth idle, high vacuum an even able to run efi, usually on an off the shelf cam it is true. Lobe separations on 383-406 cids.104-106-108-110? by SStrokerAce Sun Dec 07, 2008 12:22 am, Post In general, a stock replacement camshaft with duration of less than 200 degrees will have a lobe separation angle of more than 114 degrees. Next up was the 112-degree cam, which actually lost out in peak power slightly to the 120-degree cam, but offered considerably more torque. Depending on the engine combination, the opposite results can occur. It also depends on what the vehicle will be used for and if economy and vacuum are important. Because during the lower units oil change, you can go through the issue that the lower plug, Read More Yamaha Lower Unit Drain Plug Size [Explained Everything]Continue, Among the crucial parts of a vehicle ignition system is the ignition coil, also called a spark coil. But, you may find it quite shocking that the piston-to-valve clearances decreasing rate raises the chance of damaging the valve by the piston. When you purchase through links on our site, we may earn an affiliate commission, which supports our community. . Everyone has a different idea of gentle.While its true that the duntov cam may seem rough in a 283 it is still a factory offering and they never go to radical on there profiles for street cars.If you want a rough idle, try a 283 with a .550'lift roller and 13.5 to 1 compression,THATS ROUGH. It should still make close to 600hp and 600tq in my 512" stealth headed big block. by MELWAY Sat Dec 06, 2008 4:18 pm, Post JavaScript is disabled. 10 Tuning the timing curve and fuel from the 42-lb/hr FAST injectors was handled by this Holley HP management system. If you're an OEM automaker looking for a steady idle, good fuel economy, and passing tailpipe emissions, this is the cam of choice. The power and torque curve lay directly in between the last two cams, as did the peak horsepower and torque, 488.7 at 6,200 rpm and 487.1 at 4,600 rpm, respectively. 2.1.2.4.2 Side-lobe suppression shall be provided in accordance with the provisions of 3.1.2.1.5.2.1 on all Mode S-only all-call interrogations. 07 Though the CNC-ported heads offered plenty of flow, it was necessary to upgrade the supplied valvesprings. Increased overlap improves upper RPM power. TH400 Vs Powerglide: Which One is Ideal for You? Nothing makes mouths drop like a car that sounds and looks like it can't keep it self still! 108: 110: 112: 114 . But, you may wonder knowing that a higher valve clearance rate reduces the chance of damaging the valve by the piston. My lift will be about .580" intake and exhaust, with about 230/236 duration with a 1.7 rocker ratio, utilizing a Jesel shaft rocker system. On a tight lobe separation, like 106-108 degrees, the engine will build torque quickly and reach its peak early. by mrsmythe Wed May 14, 2003 2:26 am, Post its got a 3.73 posi and the Stock 4 speed with a very low 3.42 1st gear. I just bought a 86b Webcam with 112 lobe centers for my 2276. 108 is very tight producing lower vacuum and more of a 2 stroke "punch" powerband. Some of the programs like engine analyzer pro and dynomation seem to like some of the wider lsa's.Thanks again JOE. That means your engine can produce more power with a minimum amount of fuel combustion. Coupled that with the low first gear of the five speed, it ought to create some real traction problems.